Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Articles by George John
Page 30 of 79
Update two separate arrays in a document with one update call in MongoDB?
To update two separate arrays in a MongoDB document with a single update call, use the $push operator with multiple field specifications in the update document. This allows you to add values to multiple arrays simultaneously. Syntax db.collection.update( { "query": "condition" }, { $push: { "arrayField1": "value1", "arrayField2": "value2" ...
Read MoreIs it possible to rename _id field after MongoDB group aggregation?
Yes, it is possible to rename the _id field after MongoDB group aggregation using the $project stage. This technique allows you to map the _id field to a new field name while excluding the original _id from the output. Syntax db.collection.aggregate([ { $project: { _id: 0, newFieldName: "$_id", otherFields: ...
Read MoreHow can I to know if my database MongoDB is 64 bits?
You can use buildInfo along with runCommand to check whether your MongoDB database is running on 32-bit or 64-bit architecture. The key field to look for in the output is "bits". Syntax use admin db.runCommand("buildInfo") Example First, switch to the admin database and then run the buildInfo command ? use admin db.runCommand("buildInfo"); switched to db admin The output will display detailed build information about your MongoDB instance ? { "version" : "4.0.5", "gitVersion" : "3739429dd92b92d1b0ab120911a23d50bf03c412", ...
Read MoreHow to create an index with MongoDB?
To create an index in MongoDB, use the createIndex() method (replaces the deprecated ensureIndex()). Indexes improve query performance by creating efficient data lookup structures. Syntax db.collection.createIndex( { field: 1 }, // 1 for ascending, -1 for descending { unique: true } // optional: index options ); Create Sample Collection db.createCollection("creatingUniqueIndexDemo"); { "ok" : 1 } Example: Creating ...
Read MoreClearing items in a nested MongoDB array?
To clear items in a nested MongoDB array, use the $set operator to replace the entire array field with an empty array []. This removes all elements from the specified array field. Syntax db.collection.update( { "matchField": "value" }, { $set: { "arrayField": [] } } ); Sample Data Let us create a collection with nested arrays ? db.clearingItemsInNestedArrayDemo.insertOne({ "StudentName": "John", "StudentDetails": [ { ...
Read MoreMongoDB query to return only embedded document?
While MongoDB doesn't return only embedded documents directly, you can use projection to return specific fields and the $elemMatch operator to filter array elements that match certain conditions. Syntax db.collection.find( { "arrayField.nestedField": { $gte: value } }, { "arrayField": { $elemMatch: { "nestedField": { $gte: value } } } } ); Sample Data db.queryToEmbeddedDocument.insertOne({ "UserName": "Larry", "PostDetails": [ { "UserMessage": "Hello", "UserLikes": 8 }, ...
Read MoreIncrement a value in a MongoDB nested object?
To increment a value in a MongoDB nested object, use the $inc operator combined with the $ positional operator to target the specific nested element and increment its numeric value. Syntax db.collection.update( {"nestedArray.field": "matchValue"}, { $inc: { "nestedArray.$.fieldToIncrement": incrementValue } } ); Create Sample Data Let us create a collection with a document containing nested array objects ? db.incrementValueDemo.insertOne({ "StudentName": "Larry", "StudentCountryName": "US", "StudentDetails": [ ...
Read MoreHow to create double nested array in MongoDB?
To create a double nested array in MongoDB, use insertOne() or insertMany() with documents containing arrays of objects that themselves contain arrays. A double nested array means an array within an array structure. Syntax db.collection.insertOne({ "field1": "value1", "outerArray": [ { "innerField": "value", "innerArray": [ ...
Read MoreDifference between strncmp() and strcmp() in C/C++
Both strncmp() and strcmp() are used in C/C++ programs for lexicographical string comparison. The strcmp() compares two strings till the null character is found, whereas strncmp() only compares a specified number of characters. What is strncmp() ? The function strncmp() is used to compare left string to right string up to a number. It works same as strcmp(). It returns a value greater than zero when the matching character of left string has greater ASCII value than the character of the right string. Returns a value less than zero when the matching character of left string has lesser ASCII value ...
Read MoreUsing "SPELL AMOUNT" function to convert amounts in ABAP
You can use the standard function module SPELL_AMOUNT in ABAP to convert numeric amounts into their corresponding word representations. This is particularly useful for financial documents, checks, and reports where amounts need to be displayed in written form. To access and explore this function module, use Transaction code SE37 (Function Builder) − Click on the Search icon and select Function module SPELL_AMOUNT − Key Parameters The SPELL_AMOUNT function module accepts several important parameters − ...
Read More